Electric switch.



H. R. CAN-HELD.

ELECTRIC SWITCH. APPLICATION m0 H8. 9, m1.

1 214,752. Patented Feb. 6, 1917.

WIN/E3555 i V f/VVE/VI'OR iffii w Maw 5W UNITED STATES PATEN l HARRY B. GANFIELD, OF CLEVELAND, OHIO, .ASSIGNOR TU AND MANUFACTURING OOMPANY,OF CLEVELAND, UHIG, A CG ELECTltI-C SWITCH.

0 all whom it may concern:

Be it known that I, HARRY R. CANFIELD, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented. new and useful Improvements in Electric Switches, of. which the following is specification.

My invention relates to electric switches of the niagnetically-operated types.

The objects thereoi are to provide a seli contained. switch of this type which will not close its contacts so long as the current fiowing through its actuating winding is above a predetermined value; to provide a switch of this character in which the amount of the current necessary to prevent the actuation of the same may he changed at will; and to provide a switch. which has but few parts and is cheap construct. Other objects will appear hereinafter.

Referring to the accompanying drawing, Figure l is a vertical section showing one form of the present invention, parts being shown in side elevation. Fig. is a front elevation thereof,

On the drawing, 1 is an insulating base to which I-secure the magnet frame 2 of mag netic material, such as cast-iron. This frame may be made in various shapes, but I have shown it with the upper and lower arms or poles 3 and 4.

5, 5 are the stationary contacts which are secured to the base 1, and 6 is the movable contact which is shown connected to the upper end of the vertical reciprocatory rod 7 made preferably of non-magnetic material. To the lower end of the rod 7 I secure the plunger or armature 8 composed of mag netic material, such as soft steel. I provide the armature 8 preferably with an extension 9 of preferably smaller cross-area than that of the armature, which extension may be made integral with the armature. The eX- tension 9 is provided with the non-magnetic separator 10 which I show in the form of a sleevesecured thereto. The' extension 9 with the separator 10 thereon reciprocates in an opening through the arm 4, and the rod 7 reciprocates through the plug 11 seated in an opening in the arm 3, the plug being provided with the shoulder 12 which normally rests on the top of the arm 3 and limits its downward movement. The contact 6 rests on the top of the plug 11 when 1t 15 in its Specification of Flatter-S Patent.

16 as I accomplish by adios 1 hpplioatioh filed February 9, 1911. Serial T530. @2569.

normal unoperzted position which is that 5 shown on the The parts are so proportioned tl the contact is in its unopcrated there is an a in 155, which i 1 out gap, hetwecr l the lockhe armaso ture and that part or the separator 10, the being prefe'ahly elcvc part of the arm i to pro ular boss .14.. The top of separated $5 from the arrn 3 ny the air-nap 153, which. I call the operating gap. l I

end oi the windin of the w holes in the arms 21 venting the screws a tally turning.

The up principles of the switch cations, Serial Number 588, teinber 21, 1910, and Ee iai h uinher filed January 1911. the said applica tions 1 show a means for adjusting the length of. the lower or lockout 13. In the present application. I accomplish the same results, by adjustment oi the winding 5;; the length of U the lock-out air-gap of my prior application.

If the winding 16 is above definite or predetermined. value, the weight of the plunger and the parts inovahly connected thereto togetlier with the magnetic pull in the lock-out gap 13, that is, between the armature 8 and. the poie 42, is greater than the magnetic pull inlthe opposite direction in the operating gap 15, that is, between the armature 8 and the pole 8, thereby causing the armature and the Contact 6 to remain unactuated, as shown on the'drawir g. the ekcitation of the wind ng he iinished. to the said value, the all on armature will o edo 7 c operating av tie ends threadedor pre- 1 irons. accidengap 15, cans 1,; the pole 3 and contacts 5. After the armature has been actuated as described, the gap 15 is reduced so that the armature 8 will remainin its actuated position with a very small amount of excitation in the winding 16. If the current in the winding 16 is initially below the amount required to prevent the actuation of the armature, which amount of current may be termed the look-out value, the armature will be actuated, that is, moved toward the pole .3, provided the current in the winding 16 is at or above a minimum value, which is just suiiicient to actuate the armature. By raising the winding 16 I raise the lockout value, that is, the value of the current in the winding which will prevent the actuation of the armature, or lock open the contacts of the switch; conversely, by lowering the winding, I lower the said lock-out value of the energizing current necessary to lock out the armature and parts carried thereby. I do not limit myself to any definite means for adjusting the winding lengthwise of the armature; in fact, it is essential only that the winding and the armature be relatively movable. 1 do not limit myself to the precise details and combinations shown since they may bothbe varied without departing from the spirit ofmy invention. 1 do not limit myself to any theory of the operation of my invention. The magnetic flux appears to flow in a divided path in a part of the magnetic circuit, when the Wind ing is energized. Supposing the magnetic flux to flow from the arm or pole 3 across the gap 15, it would travel along the armature or plunger 8 to the bottom thereof, where it would divide into two paths, one path being through. the extension 9 to the arm or pole 4, and the oth er path being through the gap 13 to the arm or pole 4, where the two paths unite, the flux from the two paths passing along the back of the frame 2 to the arm or pole 8. The flux flowing across the gap 15 produces a force tending to raise the armature; the flux through the gap 13 produces a force tending to prevent the armature from being raised. When the winding is excited at a low or an, operating value, the larger art of the magnetic flux produced thereby will flow through the extension 9, which will have notendency to prevent the armature thereby into netizing the circuit, there gaps for preventing from rising, the magnetic flux in the gap 13 being too small to overcome the pull of the magnetic flux in the gap 15, through which the entire magnetic flux flows. When the winding is excited at a high or lock-out value, the restricted area of the magnetic circuit in the extension 9 forces more magnetic flux to pass into the pole 4 by way of the airgap 13, thereby increasing the force tending to prevent the upward movement of the armature. for the magnetic flux may be variously constructed and located so long as the flux in one path prevents the operation of the armature or other moving element by the flux in another part of the magnetic circuit upon the excitation above a predetermined value of the winding generating the magnetic flux. If a magnetic flux is generated and applied in any manner to prevent the actuation of the armature or its equivalent, provided the exciting winding is energized above a prede termined value, and if the winding and the armature have relative adjustment that changes'the lock-out value of. the current necessary to prevent the operation of the armature, the same will embody the principles of the invention covered by this application.

I claim- 7 y In an electro-magnetic switch, a switch contact, a movable member of magnetic material, a second switch contact movable engagement with the firstnamed contact, a magnetic circuit including the movable member, a winding for magbeing a gap in the circuit adjacent to each end of the movable member, a magnetic shunt around one of the movable member to close the switch by current inthe winding above a predetermined value, and means toradjusting the winding in the direction of its axis to vary the relation of the magnetic pulls at the gaps.

Signed at Cleveland, Ohio. this 30th day of January, it. D. 1911.

I HARRY R. CANFIETJ). Witnesses:

R. H. BENNETT, H. M DmMnn.

The parallel, or divided, paths" the operation of the 

